CN111072799A - Method for separating vinyl chloride-vinyl acetate copolymer synthesized by solution polymerization method - Google Patents
Method for separating vinyl chloride-vinyl acetate copolymer synthesized by solution polymerization method Download PDFInfo
- Publication number
- CN111072799A CN111072799A CN201911318102.7A CN201911318102A CN111072799A CN 111072799 A CN111072799 A CN 111072799A CN 201911318102 A CN201911318102 A CN 201911318102A CN 111072799 A CN111072799 A CN 111072799A
- Authority
- CN
- China
- Prior art keywords
- vinyl chloride
- vinyl acetate
- solution
- acetate copolymer
- vinyl
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F6/00—Post-polymerisation treatments
- C08F6/06—Treatment of polymer solutions
- C08F6/12—Separation of polymers from solutions
Abstract
The invention relates to synthesis of vinyl chloride-vinyl acetate copolymer, in particular to a separation method of vinyl chloride-vinyl acetate copolymer synthesized by a solution polymerization method. Adding low-carbon alcohol as a settling agent into the vinyl chloride-vinyl acetate resin solution synthesized by a solution polymerization method, stirring to enable the system to be in a full liquid phase, and carrying out settling separation at least once to obtain loose solid resin. The obtained vinyl chloride-vinyl acetate copolymer has good solubility in ketone and ester solvents, the obtained solution is not yellowed, the transparency after dissolution is high, and the separation process is simple and easy to operate. The vinyl chloride-vinyl acetate copolymer prepared by the method can be widely applied to the fields of solvent ink, high-grade paint, packaging and the like.
Description
Technical Field
The invention relates to synthesis of vinyl chloride-vinyl acetate copolymer, in particular to a separation method of vinyl chloride-vinyl acetate copolymer synthesized by a solution polymerization method.
Background
Vinyl chloride-vinyl acetate copolymers, which also include minor amounts of other comonomers, such as maleic acid, acrylates, and the like. The vinyl chloride copolymer resin, which is the most productive one of the vinyl chloride copolymer resins, has important applications in the fields of ink, coating and packaging due to its good properties.
The vinyl chloride-vinyl acetate copolymer prepared by the solution polymerization method has the advantages of good solubility, high solution transparency, low polymer molecular branching degree, no yellowing of the solution after long-term storage and the like. Compared with suspension polymerization and emulsion polymerization methods, the method has obvious performance advantages in the application fields of high-grade paint, solvent ink and the like.
The synthesis of the solution-method vinyl chloride-vinyl acetate copolymer mainly comprises the steps of polymerization, separation, solvent and monomer recovery.
The polymerization part is vinyl chloride, vinyl acetate and other comonomers are polymerized in a proper solvent under the action of an initiator to form a vinyl chloride-vinyl acetate polymer solution, and according to the difference of polymerization conversion rates, the solution contains unreacted monomers and residual initiator besides the vinyl chloride-vinyl acetate polymer and the solvent.
The separation refers to the step of extracting the polyvinyl chloride-vinyl acetate resin from the polymer solution formed after the polymerization of the polyvinyl chloride-vinyl acetate resin to form loose solid resin for transportation and use, and the step is also the most difficult step in the synthesis of the polyvinyl chloride-vinyl acetate resin by a solution method. The polymerized vinyl chloride-vinyl acetate resin solution mainly comprises resin, solvent and unreacted monomer, if the resin is not properly treated, the treated resin contains a large amount of monomer and solvent, so that the resin becomes sticky jelly, is difficult to dry and crush and cannot become powder or granular products.
The documents for preparing the vinyl chloride-vinyl acetate copolymer by a solution method are less reported, in the US patent US2345660, vinyl chloride and vinyl acetate are dissolved in acetone solvent, hydrogen peroxide is added as a catalyst, the reaction is carried out for 5 to 7 hours at the temperature of 40 ℃, the monomer conversion rate is 43 to 47 percent, and the vinyl chloride content in the obtained vinyl chloride-vinyl acetate copolymer is 85 percent. The defects that the hydrogen peroxide used as the catalyst is easy to decompose when meeting metals, and a reaction kettle needs special treatment.
In US2075575, vinyl chloride and vinyl acetate are reacted in acetone as a solvent in the presence of a small amount of acetic acid at 60 ℃ for 33 hours using benzoyl peroxide as a catalyst to prepare a vinyl chloride-vinyl acetate copolymer.
The above patent does not relate to the separation of polymer solutions.
In chinese patent 201110233888.X, vinyl chloride, vinyl acetate and an initiator are subjected to a polymerization reaction in a mixed solvent of acetone and cyclohexane for 22 hours to obtain a polymer solution. Adding the reaction liquid into an isopropanol aqueous solution under high-speed stirring, and then dropwise adding the reaction liquid into an isopropanol and water mixed solution to form spherical particles. And filtering, washing the filter cake, and finally filtering and drying to obtain the solid particles of the vinyl chloride-vinyl acetate copolymer.
The separation method reported above is very easy to produce viscous polymer precipitate in the process of high-speed mixing of polymer solution and isopropanol aqueous solution, and the process is difficult to control; in the process of dropwise adding the mixture into the mixed solution of isopropanol and water, the generated precipitate particles are very easy to adhere to each other, and the solvent and the monomer remain in the precipitate particles, so that the solid particles are difficult to completely dry. The treatment method has high requirements on operation technology and low production efficiency, and is not beneficial to large-scale industrial production.
Disclosure of Invention
The invention aims to provide a method for separating vinyl chloride-vinyl acetate copolymer synthesized by a solution polymerization method.
In order to achieve the purpose, the invention adopts the technical scheme that:
a method for separating the vinyl chloride-vinyl acetate copolymer synthesized by solution polymerization includes such steps as adding low-carbon alcohol as settling agent to the vinyl chloride-vinyl acetate copolymer solution, stirring to make the system in full liquid phase, and settling for at least one time.
The settling agent is added to keep the system materials in a liquid state, and settling separation is carried out at 10-80 ℃, preferably 30-60 ℃; the amount of precipitant added is 50-300 wt% of the polymer solution, and the amount of precipitant added is such that the material in the separation vessel remains in a liquid state, and the amount of precipitant added per separation is typically 50-300 wt%, preferably 100-200 wt% of the polymer solution.
The separation temperature is required to keep the materials in the separation kettle in a liquid state, and the materials in the separation kettle are in a liquid phase state in the sedimentation separation process. Generally, the required requirements can be met by two times of sedimentation separation, and one or more times of sedimentation separation are also in the scope of the implementation.
Transferring the vinyl chloride-vinyl acetate resin solution synthesized by the solution polymerization method into a separation kettle, heating to 10-80 ℃, adding a settling agent under the stirring condition, continuously stirring until the interior of the kettle is in a full liquid phase state, standing and layering the solution in the kettle into two layers, and collecting the lower layer solution;
adding the settling agent into the lower layer liquid, heating to 10-80 deg.C, stirring until the solution in the kettle is in a full liquid phase state, separating the solution in the kettle into two layers, discharging the lower layer solution, drying, and pulverizing to obtain the final product.
The settling agent is methanol, ethanol, isopropanol, n-butanol or pentanol.
The vinyl chloride-vinyl acetate copolymer solution synthesized by the solution polymerization method is prepared by adding a solvent, a monomer and an initiator into a high-pressure reaction kettle, introducing a vinyl chloride monomer after replacing air in the reaction kettle with nitrogen, and heating the reaction kettle to perform polymerization reaction; and after the reaction is finished, removing the residual vinyl chloride monomer to obtain a vinyl chloride-vinyl acetate copolymer solution containing residual vinyl acetate and other comonomers for later use.
The mass concentration of the polymer solution is 10-50%, preferably 15-30%. If the concentration of the polymerization solution is too high, the polymerization solvent may be diluted to a desired concentration.
The invention has the advantages that:
the invention separates polymer solution by adopting a liquid-liquid separation method. Thermoplastic resin vinyl chloride-vinyl acetate copolymer is used and is in a flowable liquid state at a certain temperature, and then a solvent which is not mutually soluble with the thermoplastic resin vinyl chloride-vinyl acetate copolymer is added to reduce the softening point of the thermoplastic resin vinyl chloride-vinyl acetate copolymer. And then a third-party solvent which is mutually soluble with the monomer and the polymerization reaction solvent and insoluble in the vinyl chloride-vinyl acetate copolymer is introduced as a settling agent, and the resin can be in a flowable liquid state in the separation process by controlling the amount of the settling agent and the treatment temperature in the separation process by utilizing the principle that the softening point of the vinyl chloride-vinyl acetate copolymer is reduced in the settling agent. The liquefied vinyl chloride-vinyl acetate copolymer is positioned at the lower layer and the unreacted monomer, the reaction solvent and the settling agent are positioned at the upper layer by utilizing the specific gravity difference of the resin, the monomer and the solvent, and the unreacted monomer and the polymerization solvent are removed by adopting a liquid-liquid separation method. The treatment method has the advantages of simple process, short treatment time and good separation effect. And loose solid resin powder or particles can be obtained by cooling, drying and crushing at the later stage, and the method is suitable for large-scale industrial production.
The invention ensures that the whole material is in a liquid state when the vinyl chloride-vinyl acetate copolymer solution is separated by selecting a proper settling agent and a proper separation temperature. The method can conveniently separate the polymer solution of the vinyl chloride-vinyl acetate copolymer to be treated to obtain the solid resin, and has strong operability. The treatment method has no special requirements on the molecular weight and the composition of the vinyl chloride-vinyl acetate resin, and can treat various vinyl chloride-vinyl acetate resins synthesized by adopting a solution polymerization method.
The treatment method has simple process and has no special requirement on the early polymerization process; the treatment time is short, and the separation effect is good; and loose solid resin powder or particles can be obtained by cooling, drying and crushing at the later stage, and the method is suitable for large-scale industrial production.
Detailed Description
The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes and modifications of the present invention may be made by those skilled in the art after reading the teachings of the present invention, and such equivalents are also within the scope of the present invention as defined in the appended claims.
The invention adopts a liquid-liquid separation method to separate the vinyl chloride-vinyl acetate copolymer from the reaction solution thereof, so as to obtain loose solid vinyl chloride-vinyl acetate copolymer. The obtained vinyl chloride-vinyl acetate copolymer has good solubility in ketones and esters, the obtained solution is not yellowed, the transparency after dissolution is high, and the separation process is simple and easy to operate. The vinyl chloride-vinyl acetate copolymer prepared by the method can be widely applied to the fields of solvent ink, high-grade paint, packaging and the like.
Preparation examples
Example 1
80.0 g of vinyl acetate, 0.56 g of benzoyl peroxide, 240 g of acetone and 240 g of toluene are respectively added into a 1L polymerization kettle and replaced by nitrogen; adding 192 g of vinyl chloride monomer into the reaction kettle, heating to 60 ℃, reacting for 6.5 hours, cooling to room temperature, finishing the reaction, and replacing unreacted vinyl chloride in the polymerization kettle with nitrogen; 708 g of polymer solution were obtained. Through measurement, the polymerization conversion rate is 54%, the polymerization solution contains 40 g of vinyl acetate monomer, 146.9 g of polymer and the mass concentration of the polymer solution is 20.7% except the solvent.
The polymer solution is added into a 3L separation kettle, 1400 g of methanol is added, stirring is started, the rotating speed is 250 r/min, the temperature is raised to 40 ℃, and stirring is continued for 10 minutes at the temperature. Stopping stirring, and separating the materials in the kettle into two layers. The upper layer liquid was removed, 1400 g of methanol was added, and the temperature was raised to 55 ℃ at the same rotational speed, and further stirring was continued for 15 minutes. Stopping stirring, and separating the materials in the kettle into two layers. The lower layer material is discharged and cooled to room temperature to become solid, and 146.0 g of white powdery vinyl chloride-vinyl acetate copolymer can be obtained after crushing and drying, and the specific indexes are shown in table 1.
Example 2
According to the experimental method described in example 1, vinyl chloride, vinyl acetate and maleic acid were polymerized in the presence of a solvent and a catalyst to obtain 500 g of a polymer solution of a vinyl chloride-vinyl acetate terpolymer containing 141.1 g of vinyl chloride-vinyl acetate, 2 g of maleic acid, 25 g of vinyl acetate and 331.9 g of acetone, and having a resin content of 28.2%.
Adding the polymer solution into a separation kettle, adding 750 g of methanol, starting stirring at the rotation speed of 250 rpm, heating to 35 ℃, and stirring for 10 minutes at the temperature. Stopping stirring, and separating the materials in the kettle into two layers. The upper layer liquid was removed, and 800 g of methanol was added thereto, and the mixture was heated to 50 ℃ at the same rotation speed, and stirred for 15 minutes. Stopping stirring, and separating the materials in the kettle into two layers. The lower layer material is discharged and cooled to room temperature to become solid, and 139.9 g of white powdery vinyl chloride-vinyl acetate copolymer can be obtained after crushing and drying, and the specific indexes are shown in table one.
Example 3
According to the experimental method described in example 1, vinyl chloride and vinyl acetate were polymerized in the presence of a solvent and a catalyst to obtain 800 g of a vinyl chloride/vinyl acetate copolymer solution containing 120 g of vinyl chloride/vinyl acetate, 18 g of vinyl acetate and 662 g of methyl ethyl ketone, and having a resin content of 15%.
Adding the polymer solution into a separation kettle, adding 1500 g of ethanol, starting stirring at the rotation speed of 250 rpm, heating to 30 ℃, and stirring for 10 minutes at the temperature. Stopping stirring, and separating the materials in the kettle into two layers. The upper layer liquid was removed, 1500 g of ethanol was added, and the mixture was heated to 45 ℃ at the same rotational speed and stirred for 15 minutes. Stopping stirring, and separating the materials in the kettle into two layers. The lower layer material was discharged and cooled to room temperature to become a solid, which was pulverized and dried to obtain 119 g of white powdery vinyl chloride-vinyl acetate copolymer, the specific indices of which are shown in Table 1.
Example 4
According to the experimental method described in example 1, vinyl chloride, vinyl acetate and hydroxyethyl acrylate were polymerized in the presence of a solvent and a catalyst to obtain 500 g of a polymer solution of a vinyl chloride-vinyl acetate terpolymer containing 150 g of vinyl chloride-vinyl acetate, 20 g of vinyl acetate, 8 g of hydroxyethyl acrylate and 272 g of ethyl acetate, and having a resin content of 30%.
Adding the polymer solution into a separation kettle, adding 600 g of isopropanol, starting stirring at the rotation speed of 250 revolutions per minute, heating to 50 ℃, and stirring for 10 minutes at the temperature. Stopping stirring, and separating the materials in the kettle into two layers. The upper layer liquid was removed, 700 g of isopropyl alcohol was added thereto, and the mixture was heated to 58 ℃ at the same rotation speed and stirred for 15 minutes. Stopping stirring, and separating the materials in the kettle into two layers. The lower layer material was discharged and cooled to room temperature to become a solid, which was then pulverized and dried to obtain 148.6 g of white powdery vinyl chloride-vinyl acetate copolymer, the specific indices of which are shown in Table 1.
Comparative example 1
500 g of polymer solution prepared by the method of example 4 is added into 150 g of isopropanol-water (the mass ratio is 85:15) by stirring at a high speed of 600-800 r/min, the mixture is stirred uniformly, the obtained polymer emulsion is dripped into 500 g of isopropanol-water (the mixture ratio is the same as that of the previous solution) solution, and the polymer is solidified for 3 to 4 hours at the temperature of 5 ℃ and is precipitated in the form of spherical particles.
TABLE 1 indexes of the vinyl chloride-vinyl acetate resins obtained in the examples
As can be seen from Table 1, the obtained vinyl chloride-vinyl acetate copolymer has good solubility in ketones and esters, the obtained solution is not yellowed, the transparency after dissolution is high, and the separation process is simple and easy to operate. The vinyl chloride-vinyl acetate copolymer prepared by the method can be widely applied to the fields of solvent ink, high-grade paint, packaging and the like.
Claims (6)
1. A method for separating vinyl chloride-vinyl acetate copolymer synthesized by a solution polymerization method is characterized by comprising the following steps: adding low-carbon alcohol as a settling agent into the vinyl chloride-vinyl acetate resin solution synthesized by a solution polymerization method, stirring to enable the system to be in a full liquid phase, and carrying out settling separation at least once to obtain loose solid resin.
2. The method for separating vinyl chloride-vinyl acetate copolymer synthesized by the solution polymerization process as set forth in claim 1, wherein: the settling agent is added to keep the system materials in a liquid state, and settling separation is carried out at the temperature of 10-80 ℃; the addition amount of the precipitant is 50-300% of the weight of the polymer solution.
3. The method for separating a vinyl chloride-vinyl acetate copolymer synthesized by the solution polymerization method as set forth in claim 1 or 2, wherein: transferring the vinyl chloride-vinyl acetate resin solution synthesized by the solution polymerization method into a separation kettle, heating to 10-80 ℃, adding a settling agent under the stirring condition, continuously stirring until the interior of the kettle is in a full liquid phase state, standing and layering the solution in the kettle into two layers, and collecting the lower layer solution;
adding the settling agent into the lower layer liquid, heating to 10-80 deg.C, stirring until the solution in the kettle is in a full liquid phase state, separating the solution in the kettle into two layers, discharging the lower layer solution, drying, and pulverizing to obtain the final product.
4. The method for separating vinyl chloride-vinyl acetate copolymer synthesized by the solution polymerization process as set forth in claim 1, wherein: the settling agent is methanol, ethanol, isopropanol, n-butanol or pentanol.
5. The method for separating vinyl chloride-vinyl acetate copolymer synthesized by the solution polymerization process as set forth in claim 3, wherein: the vinyl chloride-vinyl acetate copolymer solution synthesized by the solution polymerization method is prepared by adding a solvent, a monomer and an initiator into a high-pressure reaction kettle, introducing a vinyl chloride monomer after replacing air in the reaction kettle with nitrogen, and heating the reaction kettle to perform polymerization reaction; and after the reaction is finished, removing the residual vinyl chloride monomer to obtain a vinyl chloride-vinyl acetate copolymer solution containing residual vinyl acetate and other comonomers for later use.
6. The method for separating vinyl chloride-vinyl acetate copolymer synthesized by the solution polymerization process as set forth in claim 5, wherein: the mass concentration of the polymer solution is 10-50%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911318102.7A CN111072799A (en) | 2019-12-19 | 2019-12-19 | Method for separating vinyl chloride-vinyl acetate copolymer synthesized by solution polymerization method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911318102.7A CN111072799A (en) | 2019-12-19 | 2019-12-19 | Method for separating vinyl chloride-vinyl acetate copolymer synthesized by solution polymerization method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111072799A true CN111072799A (en) | 2020-04-28 |
Family
ID=70315744
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911318102.7A Withdrawn CN111072799A (en) | 2019-12-19 | 2019-12-19 | Method for separating vinyl chloride-vinyl acetate copolymer synthesized by solution polymerization method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111072799A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109627373A (en) * | 2018-12-20 | 2019-04-16 | 内蒙古掌迈环保新材科技有限公司 | A method of vinyl chloride-vinyl acetate resin is prepared using solution polymerization process |
-
2019
- 2019-12-19 CN CN201911318102.7A patent/CN111072799A/en not_active Withdrawn
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109627373A (en) * | 2018-12-20 | 2019-04-16 | 内蒙古掌迈环保新材科技有限公司 | A method of vinyl chloride-vinyl acetate resin is prepared using solution polymerization process |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101175779B (en) | Method for producing vinyl chloride-vinyl acetate copolymers in the form of their solid resins | |
| CN104250334A (en) | Vinyl chloride-acrylic ester copolymer and preparation method thereof | |
| CN113248645B (en) | Low-melting point polyvinyl alcohol and preparation method thereof | |
| CN112592418A (en) | Preparation method of polyvinyl alcohol special for optical film | |
| GB2096624A (en) | Process for the preparation of cross-linked acrylic elastomers | |
| WO2023179335A1 (en) | Post-treatment process for carbon-dioxide-based biodegradable multipolymer, and use thereof | |
| JP4494473B2 (en) | Method and apparatus for producing polyvinyl alcohol having a high degree of polymerization | |
| Guo et al. | Agitating transformation during vinyl chloride suspension polymerization: aggregation morphology and PVC properties | |
| KR20080051399A (en) | Apparatus and method for recovering polymer | |
| CN113214418B (en) | Preparation method of high-porosity polyvinyl chloride | |
| WO2018105962A1 (en) | Method for manufacturing vinyl chloride based resin composition | |
| CN111072799A (en) | Method for separating vinyl chloride-vinyl acetate copolymer synthesized by solution polymerization method | |
| CN1285638C (en) | Production of polylactic and copolymer PLGA | |
| CN109181184A (en) | A kind of food-grade polyethylene alcohol water soluble film and its preparation process | |
| CN109627373A (en) | A method of vinyl chloride-vinyl acetate resin is prepared using solution polymerization process | |
| US3030341A (en) | Manufacture of prepolymers | |
| CN111004345A (en) | Continuous separation method of vinyl chloride-vinyl acetate copolymer synthesized by solution polymerization method | |
| KR101778761B1 (en) | Production method of poly(alkylene carbonate) particles | |
| US3424729A (en) | Process for liquid phase separation of prepolymers or precopolymers of diallylphthalates | |
| CN110642961A (en) | Preparation method of hydrophobically modified xanthan gum | |
| SE453919B (en) | SET FOR PREPARATION OF POWDER-HOMO OR COPOLYMERS OF ONE | |
| CN115677884B (en) | Process for preparing a bulk component for an olefin polymerization catalyst | |
| US4355157A (en) | Hot water precipitation of resins containing maleic anhydride | |
| JP4087917B2 (en) | Solvent slurry polymerization method of oxirane group-containing monomer | |
| CN110669187B (en) | Preparation method of redispersible fluoropolymer latex powder |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WW01 | Invention patent application withdrawn after publication | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20200428 |